1. Field of the Invention
The present invention relates generally to a fastening device having a safety release feature for use in hitching pack animals together.
2. Description of the Related Art
Devices including means for automatically releasing two bodies joined by a cord have been proposed in prior patents. While commonly including spring-biased hooks, many of these devices are of complex and costly construction. Further, they are often difficult to reset, requiring a high degree of manual dexterity or strength to position the hooks for subsequent release. By way of example, those devices known to the inventor are described below.
U.S. Pat. No. 544,568, issued Aug. 13, 1895 to Louis J. DeSailly et al, provides a safety hook for use in stables. The hook itself pivots upon the end of a bolt disposed within a cylindrical body. A series of alternatingly positioned steel cups fitted upon the bolt biases the hook against the body in its unreleased position. Upon the application of a sufficient tensile force, the steel cups are compressed and somewhat flattened, thereby allowing the upper end of the hook to be released from a catch extending outwardly from the body.
U.S. Pat. No. 602,569, issued Apr. 19, 1898 to Donald L. Turner, shows a releasing device comprising a pivoting clutch mechanism releasably secured within a tubular housing. The clutch mechanism includes two cylindrical jaws adapted to engage a ball disposed at the end of a spring biased eyebolt. Two of the housing's tubular elements are threadably connected allowing the spring tension upon the eyebolt to be varied. A set screw permits the spring tension to be fixed and prevented from varying. Thus, upon application of a force sufficient to overcome the spring's pull, the clutch may be withdrawn from the housing and the device separated into two component parts.
U.S. Pat. No. 675,453, issued Jun. 4, 1901 to George F. Sturgess, describes a coupling device for use with bicycles. The device includes a tether or cord for transmitting tensile force from one bicycle to another for towing purposes. A C-shaped spring clip is provided for securing one end of the tether to a bicycle. When a sufficient tensile force is applied thereto, the spring clip will automatically release from its supporting surface preventing harm to the riders.
U.S. Pat. No. 2,452,796, issued Nov. 2, 1948 to Ole M. Skibsted, discloses self-releasing rope hitch used when towing a plow behind a tractor. The hitch includes a circular link retained against a metal strap by a spring biased jaw member. The biasing means for the jaw member include a spring disposed upon a threaded bolt. Rotation of a nut at the end of the bolt adjusts the force imparted by the spring against the jaw member.
U.S. Pat. No. 4,186,690, issued Feb. 5, 1980 to John J. Seiler, teaches the use of a safety clip in an animal grooming tethering device. The clip includes two generally resilient parallel arms connected to one another at one end and having their free ends bent inwardly toward one another in a V-shaped configuration. A band, slidable on the arms, is provided to adjust the clip to release a tether at a predetermined force.
None of the above inventions, taken either singly or in combination, is seen to describe the instant invention as claimed.